It uses POP3 email accounts to receive subscribe and unsubscribe requests from respondents, extracts email addresses and sender names from email messages on fly, and creates plain-text files with subscribers wanting to subscribe or unsubscribe. The text files with emails can be used with any bulk mailer as mailing list files to add new subscribers and delete existing ones. The program is best optimized for working with Mail Bomber mass mailer, and although Mail Bomber has a built-in file and email subscribe and unsubscribe feature, Email Subscriber Pro lets you increase its functionality and flexibility. Email Subscriber Pro can be configured for a couple of seconds, all you need to do to get started, is to set up two POP3 email accounts for subscribe and unsubscribe email requests, and specify two words like SUBSCRIBE and UNSUBSCRIBE used for recognizing requests of different types in the incoming email.